Apparatuses and methods for heating moving continuous glass ribbons at desired lines of separation and/or for separating glass sheets from continuous glass ribbons

ABSTRACT

Apparatuses and methods for heating moving continuous glass ribbons at desired lines of separation and/or for separating glass sheets from continuous glass ribbons are disclosed. An apparatus includes a translatable support portion and a heating apparatus coupled to the support portion. The heating apparatus is configured to contact the continuous glass ribbon across at least a portion of a width of the continuous glass ribbon at the desired line of separation as the support portion moves in a draw direction, thereby preferentially applying heat to a first side of the continuous glass ribbon at the desired line of separation as the continuous glass ribbon moves in the draw direction.

This application is a divisional of U.S. patent application Ser. No.15/742,234 filed on Jul. 7, 2016, which claims the benefit of priorityunder 35 U.S.C. § 371 of International Application No.PCT/US2016/041223, filed on Jul. 7, 2016, which claims the benefit ofpriority under 35 U.S.C. § 119 of U.S. Provisional Application No.62/189,412, filed on Jul. 7, 2015, the content of which is incorporatedherein by reference in its entirety.

BACKGROUND Field

The present specification generally relates to glass manufacturingapparatuses and methods and, more specifically, to apparatuses andmethods for heating moving continuous glass ribbons at desired lines ofseparation and/or for separating glass sheets from continuous glassribbons.

Technical Background

Continuous glass ribbons may be formed by processes such as the fusiondraw process, the slot draw process, or other similar downdrawprocesses. The fusion draw process yields continuous glass ribbons whichhave surfaces with superior flatness and smoothness when compared toglass ribbons produced by other methods. Individual glass sheetssectioned from continuous glass ribbons formed by the fusion drawprocess can be used in a variety of devices including flat paneldisplays, touch sensors, photovoltaic devices, and other electronicapplications. An individual glass sheet may be sectioned from acontinuous glass ribbon by mechanically scoring or laser scoring thecontinuous glass ribbon along a scoring line and then bending thecontinuous glass ribbon at the scoring line to separate the individualglass sheet from the continuous glass ribbon. However, simply scoringand then bending to section individual glass sheets may result in lowyields and undesirable warp.

In some applications, individual glass sheets sectioned from continuousglass ribbons (e.g., cover glasses, glass backplanes, and the like)formed by downdraw processes may be employed in both consumer andcommercial electronic devices such as LCD and LED displays, computermonitors, automated teller machines (ATMs), and the like. Some of theseglass sheets may include “touch” functionality which necessitates thatthe glass sheet be contacted by various objects including a user'sfingers and/or stylus devices and, as such, the glass must besufficiently robust to endure regular contact without damage. Moreover,such glass sheets may also be incorporated in portable electronicdevices, such as mobile telephones, personal media players, and tabletcomputers. The glass sheets incorporated in these devices may besusceptible to damage during transport and/or use of the associateddevice. Accordingly, glass sheets used in electronic devices may requireenhanced strength to be able to withstand not only routine “touch”contact from actual use, but also incidental contact and impacts whichmay occur when the device is being transported. Some glass sheetsrequiring such enhanced strength may be sectioned from continuous glassribbons comprising a core layer disposed between a first cladding layerand a second cladding layer. The difference in the coefficients ofthermal expansion between the core layer and the cladding layers, aswell as bead size and shape, core to clad ratio, and position andthickness variations of such continuous glass ribbons, may make itparticularly difficult to separate glass sheets from such continuousglass ribbon by simple mechanical or laser scoring and bending at thescore line as a method of separation. Such a method of separatingindividual glass sheets from continuous glass ribbons may result inparticularly low yields and undesirable warp. Furthermore, mechanicalscoring of continuous glass ribbons is undesirably complicated byirregular surfaces and high stress present in such continuous glassribbons.

Accordingly, a need exists for alternative apparatuses and methods thatfacilitate the separation of glass sheets from continuous glass ribbons.

SUMMARY

In one embodiment, an apparatus includes a translatable support portionand a heating apparatus coupled to the support portion. The heatingapparatus is configured to contact a continuous glass ribbon across atleast a portion of a width of the continuous glass ribbon at a desiredline of separation as the support portion moves in a draw direction,thereby preferentially applying heat to a first side of the continuousglass ribbon at the desired line of separation as the continuous glassribbon moves in the draw direction.

In another embodiment, a glass manufacturing apparatus includes aforming body configured to form a continuous glass ribbon moving in adraw direction, and a translatable separation initiation unit positioneddownstream of the forming body. The translatable separation initiationunit includes a support portion, a heating apparatus coupled to thesupport portion, an insulator, and a scoring device. The heatingapparatus is configured to contact the continuous glass ribbon across atleast a portion of a width of the continuous glass ribbon at a desiredline of separation as the support portion moves in the draw direction,thereby preferentially applying heat to a first side of the continuousglass ribbon at the desired line of separation as the continuous glassribbon moves in the draw direction. The insulator is disposed betweenthe support portion and the heating apparatus. The scoring device isconfigured to initiate a flaw in the continuous glass ribbon at thedesired line of separation. The heating apparatus and the scoring deviceare positioned such that the continuous glass ribbon is disposed betweenthe heating apparatus and the scoring device when the heating apparatuscontacts the continuous glass ribbon.

In yet another embodiment, a method of separating a glass sheet from acontinuous glass ribbon includes drawing molten glass in a drawdirection at a speed S to form a continuous glass ribbon, and moving aheating apparatus in the draw direction at the speed S. The methodfurther includes applying heat preferentially to a first side of thecontinuous glass ribbon with the heating apparatus at a desired line ofseparation as the continuous glass ribbon moves in the draw direction atthe speed S. The method further includes separating the glass sheet fromthe continuous glass ribbon at the desired line of separation.

Additional features and advantages of the embodiments described hereinare set forth in the detailed description, the claims, and the appendeddrawings.

The foregoing general description and the following detailed descriptionprovide various embodiments and provide an overview or framework forunderstanding the nature and character of the claimed subject matter.The accompanying drawings provide a further understanding of the variousembodiments, and are incorporated into and constitute a part of thisspecification. The drawings and the description explain the principlesand operations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically depicts a side view of a glass manufacturingapparatus from which a continuous glass ribbon is drawn, according toone or more embodiments shown and described herein;

FIG. 2 schematically depicts a front view of the glass manufacturingapparatus of FIG. 1 , according to one or more embodiments shown anddescribed herein;

FIG. 3 schematically depicts a heating apparatus and an insulatorcoupled to a support portion of a translatable separation initiationunit, according to one or more embodiments shown and described herein;

FIG. 4 schematically depicts a heating apparatus, a thermally conductivecover, and an insulator coupled to a support portion of a translatableseparation initiation unit, according to one or more embodiments shownand described herein;

FIG. 5 schematically depicts a heating apparatus disposed within aninsulator that is coupled to a support portion of a translatableseparation initiation unit, according to one or more embodiments shownand described herein;

FIG. 5A schematically depicts a heating apparatus disposed within aninsulator that is coupled to a support portion of a translatableseparation initiation unit, according to one or more embodiments shownand described herein;

FIG. 6 schematically depicts a portion of a translatable separationinitiation unit including a heating apparatus and an opposingcounternosing, according to one or more embodiments shown and describedherein;

FIG. 7 schematically depicts a portion of a translatable separationinitiation unit including a heating apparatus and an opposingcounternosing, according to one or more embodiments shown and describedherein;

FIG. 8 schematically depicts a portion of a translatable separationinitiation unit including a heating apparatus and a pair of opposingcounternosings, according to one or more embodiments shown and describedherein;

FIG. 9 schematically depicts a side view of a continuous glass ribbonengaged by a nosing, a pair of counternosings, a heating apparatus, anda flaw initiation device, according to one or more embodiments shown anddescribed herein;

FIG. 10 schematically depicts a side view of a continuous glass ribbondisposed between a heating apparatus and a cooling apparatus, accordingto one or more embodiments shown and described herein;

FIG. 11 schematically depicts a side view of a heating apparatus andcooling apparatus disposed on the same side of a continuous glassribbon, according to one or more embodiments shown and described herein;and

FIG. 12 schematically depicts a translatable separation initiation unit,according to one or more embodiments shown and described herein.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments ofapparatuses and methods for heating moving continuous glass ribbons atdesired lines of separation and/or for separating glass sheets fromcontinuous glass ribbons, examples of which are illustrated in theaccompanying drawings. Whenever possible, the same reference numeralswill be used throughout the drawings to refer to the same or like parts.FIG. 1 schematically depicts one embodiment of an apparatus for heatinga continuous glass ribbon moving in a draw direction. The continuousglass ribbon comprises a glass material, a ceramic material, aglass-ceramic material, or a combination thereof. The apparatus includesa support portion and a heating apparatus coupled to the supportportion. The heating apparatus extends perpendicular to the drawdirection. The support portion is configured to move in concert with thecontinuous glass ribbon for a period of time such that the heatingapparatus contacts the continuous glass ribbon at a fixed location forthe period of time at a desired line of separation as the continuousglass ribbon moves in the draw direction, thereby preferentiallyapplying heat to a first side of the continuous glass ribbon at thedesired line of separation as the continuous glass ribbon moves in thedraw direction. Such preferential application of heat can establish athermal gradient through a thickness or depth of the glass ribbon at thedesired line of separation, which can aid in severing the glass ribbonat the desired line of separation to separate a glass sheet therefrom asdescribed herein. Apparatuses and methods for heating moving continuousglass ribbons at desired lines of separation and/or for separating glasssheets from continuous glass ribbons are described in more detail hereinwith specific reference to the appended figures.

Coordinate axes are included in the drawings to provide a frame ofreference for various components of the continuous glass ribbonfabrication apparatuses and methods described herein. As used herein, a“lateral” or “across-the-draw” direction is defined as the positive X ornegative X direction of the coordinate axes shown in the drawings. A“downstream” or “draw” direction is defined as the negative Z directionof the coordinate axes shown in the drawings. An “upstream” direction isdefined as the positive Z direction of the coordinate axes shown in thedrawings. A “depth” is defined in the positive Y or negative Y directionof the coordinate axes shown in the drawings.

As used herein the term “average coefficient of thermal expansion” meansthe linear coefficient of thermal expansion averaged over a temperaturerange of 20° C.-300° C.

While the apparatuses and methods described herein are used to heatand/or separate laminated continuous glass ribbons formed by the fusiondowndraw process, embodiments are not limited thereto. The apparatusesand methods described herein may be used to heat and/or separatenon-continuous glass ribbons. The apparatuses and methods describedherein may be used to heat and/or separate individual glass sheets orindividual glass sections. Furthermore, the apparatuses and methodsdescribed herein may be used to heat and/or separate laminated,non-laminated, continuous, or non-continuous glass ribbons formed fromthe slot draw process, another downdraw process, the float process, oranother glass ribbon manufacturing process.

In some embodiments, the continuous glass ribbon described herein may beformed by a fusion lamination process, such as the process described inU.S. Pat. No. 4,214,886, which is incorporated herein by reference.Referring to FIG. 1 by way of example, a glass manufacturing apparatus100 for forming a continuous glass ribbon 170 and separating a glasssheet from the continuous glass ribbon 170 includes a forming body 110,a plurality of pulling rolls 140, a translatable separation initiationunit 150, and a glass engaging unit 160.

Still referring to FIG. 1 , the forming body 110 includes an upperisopipe 120 positioned over a lower isopipe 130. The upper isopipe 120includes a trough 124 into which a molten glass cladding composition 122is fed from a melter (not shown). Similarly, the lower isopipe 130includes a trough 134 into which a molten glass core composition 132 isfed from a melter (not shown). In the embodiments, described herein, themolten glass core composition 132 has an average coefficient of thermalexpansion CTE_(core) which is greater than an average coefficient ofthermal expansion CTE_(clad) of the molten glass cladding composition122.

Still referring to FIG. 1 , as the molten glass core composition 132fills the trough 134, it overflows the trough 134 and flows over theouter forming surfaces 136, 138 of the lower isopipe 130. The outerforming surfaces 136, 138 of the lower isopipe 130 converge at a root139. Accordingly, the molten glass core composition 132 flowing over theouter forming surfaces 136, 138 rejoins at the root 139 of the lowerisopipe 130 thereby forming a glass core layer 172 of the continuousglass ribbon 170.

Simultaneously, the molten glass cladding composition 122 overflows thetrough 124 formed in the upper isopipe 120 and flows over outer formingsurfaces 126, 128 of the upper isopipe 120. The molten glass claddingcomposition 122 is outwardly deflected by the upper isopipe 120 suchthat the molten glass cladding composition 122 flows around the lowerisopipe 130 and contacts the molten glass core composition 132 flowingover the outer forming surfaces 136, 138 of the lower isopipe 130,fusing to the molten glass core composition 132 and forming glasscladding layers 174 a, 174 b around the glass core layer 172 of thecontinuous glass ribbon 170.

As noted above, the molten glass core composition 132 generally has anaverage coefficient of thermal expansion CTE_(core) which is greaterthan the average coefficient of thermal expansion CTE_(clad) of themolten glass cladding composition 122. Accordingly, as the glass corelayer 172 and the glass cladding layers 174 a, 174 b cool, thedifference in the coefficients of thermal expansion of the glass corelayer 172 and the glass cladding layers 174 a, 174 b cause a compressivestresses to develop in the glass cladding layers 174 a, 174 b. Thecompressive stress increases the strength of the resulting laminatedglass article without an ion-exchange treatment or a thermal temperingtreatment. However, such increased strength can make scoring thelaminated glass article difficult.

Still referring to FIG. 1 , the plurality of pulling rolls 140 arearranged in opposing pairs and are counter-rotating. That is, a firstpulling roll of the plurality of pulling rolls 140 is positionedadjacent to a first side of the continuous glass ribbon 170 (the “A”side of the continuous glass ribbon 170) and rotates in a directionopposite a second pulling roll of the plurality of pulling rolls 140positioned across from the first pulling roll and adjacent to a secondside of the continuous glass ribbon 170 (the “B” side of the continuousglass ribbon 170). The continuous glass ribbon 170 is positioned betweenopposing pairs of pulling rolls so that the pulling rolls contact andpinch the continuous glass ribbon 170 at the edge portions of the glassribbon, as depicted in FIGS. 1 and 2 .

Referring once again to FIG. 1 , the plurality of pulling rolls 140 aredriven by motors and apply a downward force to the continuous glassribbon 170, thereby drawing the continuous glass ribbon 170 from theforming body 110 in the draw direction. The plurality of pulling rolls140 also help support a weight of the continuous glass ribbon 170, sinceduring at least a portion of the separation cycle the portion of thecontinuous glass ribbon 170 below the plurality of pulling rolls 140 maybe unsupported. Without a suitable pinching force, the plurality ofpulling rolls 140 may be unable to apply a sufficient downward pullingforce, or may be unable to support the portion of the continuous glassribbon 170 below the plurality of pulling rolls 140 against the force ofgravity.

Still referring to FIG. 1 , the translatable separation initiation unit150 includes a support portion 152, a heating apparatus 154, and a flawinitiation device 156. The heating apparatus 154 is coupled to thesupport portion 152. The heating apparatus 154 includes a heatingelement, such as a cartridge heater, a heating rod, a heating filament,a heating wire, heat tape, or the like. In some embodiments, the heatingapparatus 154 is the heating apparatus 300 depicted in FIG. 3 anddescribed below. In some embodiments, the heating apparatus 154 is theheating apparatus 400 depicted in FIG. 4 and described below. In someembodiments, the heating apparatus 154 is the heating apparatus 500depicted in FIG. 5 and described below. The heating apparatus 154extends perpendicular to the draw direction (See FIG. 2 ). While theheating apparatus 154 extends perpendicular to the draw direction in theembodiment depicted in FIG. 2 , it should be understood that in otherembodiments, the heating apparatus 154 may not extend perpendicular tothe draw direction. For example, in some embodiments, the heatingapparatus 154 extends parallel to the draw direction. In someembodiments, the heating apparatus 154 extends at an angle between 0°and 90° relative to the draw direction.

In some embodiments, the heating apparatus 154 is configured to contactthe continuous glass ribbon 170 across at least a portion of a width ofthe continuous glass ribbon 170 (or across an entire width of thecontinuous glass ribbon 170) at a desired line of separation (“DLS”),thereby preferentially heating the continuous glass ribbon 170 at thedesired line of separation to facilitate the separation of a glass sheetfrom the continuous glass ribbon 170 at the desired line of separation.In some embodiments, the continuous glass ribbon 170 has cooledsignificantly from its temperature at the root 139 (which may be in therange of about 1000° C. to about 1200° C. in some embodiments) to itstemperature immediately prior to being contacted by the heatingapparatus 154 (which may be in the range of about 300° C. to about 400°C. in some embodiments). It should be noted that heating the continuousglass ribbon at the desired line of separation can include increasingthe temperature of the continuous glass ribbon at the desired line ofseparation or reducing the rate of cooling of the glass ribbon at thedesired line of separation. Following such heating, the temperature ofthe continuous glass ribbon at the desired line of separation is greaterthan the temperature of the continuous glass ribbon in a region thereofadjacent to and/or downstream of the desired line of separation.

In some embodiments, such as embodiments in which the heating apparatus154 extends perpendicular to the draw direction, the desired line ofseparation extends perpendicular to the draw direction across at least aportion of the width of the continuous glass ribbon 170. In someembodiments, such as embodiments in which the heating apparatus 154extends parallel to the draw direction, the desired line of separationextends parallel to the draw direction (e.g., to separate one or moreedge portions or beads from the continuous glass ribbon 170). In someembodiments, such as embodiments in which the heating apparatus 154extends at an angle between 0° and 90° relative to the draw direction,the desired line of separation extends at the same angle (e.g., toseparate angled glass sheets from the continuous glass ribbon 170). Insome embodiments, the heating apparatus 154 may not contact thecontinuous glass ribbon 170, such as when the heating apparatus 154heats the continuous glass ribbon 170 at the desired line of separationby a non-contact modality. For example, the heating apparatus 154 can bepositioned in close proximity to, but not in contact with, thecontinuous glass ribbon 170, thereby applying heat preferentially to afirst side of the continuous glass ribbon 170 at the desired line ofseparation.

In some embodiments, the heating apparatus 154 contacts the continuousglass ribbon 170 across the entire width of the desired line ofseparation. In other embodiments, the heating apparatus 154 contacts thecontinuous glass ribbon 170 across only a portion of the desired line ofseparation. For example, in some embodiments, the heating apparatus 154contacts one or more bead regions of the continuous glass ribbon 170(i.e. a relatively thick region of the glass ribbon 170 near an edgethereof) without contacting a central region of the glass ribbon (e.g.,disposed between bead regions at opposing edges of the glass ribbon).Such contact between the heating apparatus 154 and the glass ribbon 170at the bead regions can help to apply relatively more heat to the beadregions compared to the non-bead regions (e.g., the central region ofthe glass sheet). Because the bead regions are thicker than the non-beadregions of the glass ribbon, applying relatively more heat to the beadregions can help to form a temperature gradient through the thickness ofthe glass ribbon that is more uniform across the width of the glassribbon.

Referring now to FIG. 3 , a heating apparatus 300 includes a heatingelement 151. The heating element 151 is coupled to the support portion152. The heating element 151 may be a cartridge heater, a heating rod, aheating filament, a heating wire, heat tape, or the like. The heatingelement 151 may be formed from a ceramic material, a metal material,and/or a composite material. In some embodiments, the heating element151 is a conformal heating element, which may enhance the degree ofcontact between the heating element 151 and the continuous glass ribbon170 at the desired line of separation, thereby facilitating efficientthermal transfer of thermal energy from the heating element 151 to thecontinuous glass ribbon 170 at the desired line of separation.

Still referring to FIG. 3 , the heating element 151 is coupled, directlyor indirectly, to the support portion 152 by at least one wire 155.While the heating element 151 is coupled to the support portion 152 bythe at least one wire 155 in FIG. 3 , in other embodiments the heatingelement 151 may be coupled to the support portion 152 in another manner.For example, in some embodiments, the heating element 151 is coupled tothe support portion 152 by at least one fastener other than a wire, suchas a clip, a screw, a bolt, a clamp, or the like. In some embodiments,the heating element 151 is adhesively affixed to the support portion152. In some embodiments, the heating element 151 is retained within aproperly sized channel of the support portion 152. In some embodiments,the heating element 151 is coupled to the insulator 153 (e.g. by afastener such as a wire, a clip, a screw, a bolt, a clamp, adhesive, orthe like), which in turn is coupled to the support portion 152 (e.g. bythe same or a different fastener).

In the embodiment depicted in FIG. 3 , an insulator 153 is disposedbetween the heating element 151 and the support portion 152. Theinsulator 153 may thermally and/or electrically isolate the supportportion 152 from the heating element 151. In some embodiments, theinsulator 153 is an insulating tube made of alumina, though otherembodiments include an insulator 153 having a different shape and/ormade of a different material. Some embodiments do not include theinsulator 153 disposed between the heating element 151 and the supportportion 152, such as embodiments in which the heating element 151directly engages the support portion 152. In some embodiments, a narrowstrip of highly conductive material may be attached to (e.g., welded to)the heating element 151. In such embodiments, the highly conductivematerial is configured to contact the continuous glass ribbon 170 at thedesired line of separation.

Referring now to FIG. 4 , a heating apparatus 400 includes a heatingelement 151 and a thermally conductive cover 157. The heating element151 and the thermally conductive cover 157 are coupled to the supportportion 152. In the embodiment depicted in FIG. 4 , the heating element151 is disposed between the thermally conductive cover 157 and thesupport portion 152. The heating element 151 may be a cartridge heater,a heating rod, a heating filament, a heating wire, heat tape, or thelike. The heating element 151 may be formed from a ceramic material, ametal material, and/or a composite material. In some embodiments, thethermally conductive cover 157 is formed from metal, though in otherembodiments, the thermally conductive cover 157 is formed from acomposite material, or any other conductive material. The thermallyconductive cover 157 is configured to contact the continuous glassribbon 170 across at least a portion of a width of the continuous glassribbon 170 at the desired line of separation. For example, the thermallyconductive cover 157 includes a point or apex having a narrower crosssection (e.g., a narrower height in the draw direction) than the heatingelement 151. The thermally conductive cover 157 may provide a straightand/or narrow line of contact with the continuous glass ribbon 170,thereby facilitating efficient thermal transfer of thermal energy fromthe heating element 151 to a narrow line of separation on the continuousglass ribbon 170. Additionally, or alternatively, such a straight and/ornarrow line of contact provided by the thermally conductive cover 157may produce a line of concentrated mechanical stress at the desired lineof separation (e.g., when the thermally conductive cover serves as afulcrum about which the continuous glass ribbon 170 is bent).Furthermore, the thermally conductive cover 157 may also providestructural rigidity to the heating element 151.

Still referring to FIG. 4 , the heating element 151 and the thermallyconductive cover 157 are coupled to the support portion 152 by the atleast one wire 155. The at least one wire 155 passes through thethermally conductive cover 157 and secures the assembly of the thermallyconductive cover 157, the heating element 151, and the insulator 153 tothe support portion 152. While the heating element 151 and the thermallyconductive cover 157 are coupled to the support portion 152 by the atleast one wire 155 in FIG. 4 , in other embodiments the heating element151 and the thermally conductive cover 157 may be coupled to the supportportion 152 in another manner. For example, in some embodiments, theheating element 151 and the thermally conductive cover 157 are coupledto the support portion 152 with at least one fastener other than a wire,such as a clip, a screw, a bolt, a clamp, or the like. In someembodiments, the heating element 151 and the thermally conductive cover157 are adhesively affixed to the support portion 152. In someembodiments, the heating element 151 is retained within a properly sizedchannel of the support portion 152. In some embodiments, the heatingelement 151 and the thermally conductive cover 157 are coupled to theinsulator 153, which in turn is coupled to the support portion 152.

In the embodiment depicted in FIG. 4 , an insulator 153 is disposedbetween the heating element 151 and the support portion 152. Theinsulator 153 may thermally and/or electrically isolate the supportportion 152 from the heating element 151. In some embodiments, theinsulator 153 is an insulating tube made of alumina, though otherembodiments include an insulator 153 having a different shape and/ormade of a different material. Some embodiments do not include theinsulator 153 disposed between the heating element 151 and the supportportion 152, such as embodiments in which the heating element 151directly engages the support portion 152.

Referring now to FIG. 5 , a heating apparatus 500 includes a heatingelement 151. The heating element 151 is disposed within an insulator153, which in turn is coupled to the support portion 152. The heatingelement 151 may be a cartridge heater, a heating rod, a heatingfilament, a heating wire, heat tape, or the like. The heating element151 may be formed from a ceramic material, a metal material, and/or acomposite material. In some embodiments, the heating element 151 is aconformal heating element, which may enhance the degree of contactbetween the heating element 151 and the continuous glass ribbon 170 atthe desired line of separation, thereby facilitating efficient thermaltransfer of thermal energy from the heating element 151 to thecontinuous glass ribbon 170 at the desired line of separation.

In the embodiment depicted in FIG. 5 , the insulator 153 is disposedbetween the heating element 151 and the support portion 152. Theinsulator 153 may thermally and/or electrically isolate the supportportion 152 from the heating element 151. In some embodiments, theinsulator 153 is an insulating tube made of alumina, though otherembodiments include an insulator 153 having a different shape and/ormade of a different material. The heating element 151 is at leastpartially enclosed within a body of the insulator 153. In the embodimentdepicted in FIG. 5 , the heating element 151 protrudes through anelongate aperture in the insulator 153 and beyond the body of theinsulator 153 such that the heating element 151 may contact thecontinuous glass ribbon 170 at the desired line of separation whileavoiding contact between the insulator 153 and the continuous glassribbon 170, even if the continuous glass ribbon 170 bends slightly atthe point of contact with the heating element 151 (e.g., to partiallywrap around the heating element). In some embodiments, a narrow strip ofhighly conductive material may be attached to (e.g., welded to) theheating element 151. In such embodiments, the highly conductive materialis configured to contact the continuous glass ribbon 170 at the desiredline of separation.

Still referring to FIG. 5 , the insulator 153 is coupled to the supportportion 152 by at least one wire 155 that traverses the body of theinsulator 153. The wire can help to maintain the position of the heatingelement 151 within the insulator 153. For example, the wire can engagethe heating element 151 to push the heating element into an aperture inthe insulator 153 such that the heating element is secured between thewire and the insulator and protrudes beyond the insulator as shown inFIG. 5 . In some embodiments, the insulator 153 may be coupled to thesupport portion 152 in another manner, such as in embodiments in whichthe insulator 153 is adhesively affixed to the support portion 152 or inembodiments in which the insulator 153 is retained within a properlysized channel of the support portion 152. In some embodiments, theinsulator 153 is coupled to the support portion 152 with at least onefastener other than a wire, such as a clip, a screw, a bolt, a clamp, orthe like.

In various embodiments, the heating element 151 can protrude beyond theinsulator 153 by a suitable distance. For example, in the embodimentshown in FIG. 5 , the aperture in the insulator 153 has a width that isslightly less than a diameter of the heating element 151 such that theheating element 151 protrudes beyond the insulator 153 by a distanceapproximately equal to one-half of the diameter of the heating element151. In other words, the aperture in the insulator 153 is sized suchthat the insulator engages the heating element 151 approximately at amidpoint of the heating element 151 such that approximately one-half ofthe heating element 151 is disposed within the insulator 153 andapproximately one-half of the heating element protrudes beyond theinsulator 153. FIG. 5A is depicts another embodiment in which the widthof the aperture in the insulator 153 is smaller than in FIG. 5 . Thus,in the embodiment shown in FIG. 5A, the heating element 151 protrudesbeyond the insulator 153 by a shorter distance compared to theembodiment shown in FIG. 5 . In other words, in the embodiment shown inFIG. 5A, a greater proportion of the heating element 151 is disposedwithin the insulator 153, and a smaller proportion of the heatingelement 151 protrudes beyond the insulator 153 compared to theembodiment shown in FIG. 5 . In various embodiments, the insulator 151protrudes beyond the insulator 153 by a distance, for example, of atleast about 1 mm, at least about 1.5 mm, at least about 2 mm, or atleast about 2.5 mm. Additionally, or alternatively, the insulator 151protrudes beyond the insulator 153 by a distance, for example, of atmost about 50 mm, at most about 40 mm, at most about 30 mm, at mostabout 20 mm, at most about 10 mm, at most about 5 mm, at most about 4.5mm, at most about 4 mm, or at most about 3.5 mm.

Referring once again to FIG. 1 , the flaw initiation device 156 isconfigured to initiate a flaw at the desired line of separation of thecontinuous glass ribbon 170. The flaw initiation device 156 may initiatea flaw at the desired line of separation before, during, or after thecontinuous glass ribbon 170 is heated at the desired line of separationas described herein. In some embodiments, the flaw initiation device 156includes a scoring device. In embodiments that include the scoringdevice, the scoring device is configured to score the continuous glassribbon 170 across at least a portion of the desired line of separation.In some embodiments, the scoring device scores the continuous glassribbon 170 across the entire width of the desired line of separation. Inother embodiments, the scoring device scores the continuous glass ribbon170 across only a portion of the desired line of separation. Forexample, some embodiments may only score a bead region of the continuousglass ribbon 170 (i.e. a widthwise portion of the continuous glassribbon 170 that extends across the draw to a distance from an edge ofthe continuous glass ribbon 170), a knurl region of the continuous glassribbon 170 (i.e. a widthwise portion of the continuous glass ribbon 170that extends across the draw and includes a knurled pattern as a resultof contacting one or more pulling rollers), between a bead region andknurl region, a central region disposed between knurled and/or beadregions on opposing edges of the continuous glass ribbon, etc. In someembodiments, a widthwise central portion of the continuous glass ribbonmay include the glass core layer 172 disposed between the glass claddinglayers 174 a, 174 b, while bead regions at the edges of the continuousglass ribbon may only include the glass core layer 172 and no glasscladding layers 174 a, 174 b. Thus, the glass core layer 172 protrudesout from between the glass cladding layers 174 a, 174 b at the edges ofthe glass ribbon 170. In some such embodiments, the flaw initiationdevice 156 may introduce a flaw in the glass core layer 172 of one moreof the beads (which only include the glass core layer 172) at thedesired line of separation, without introducing the flaw into the glasscladding layers 174 a, 174 b. Introducing the flaw into the protrudingedges of the glass core layer 172 can be relatively easier thanintroducing a flaw into one or both of the glass cladding layers 174 a,174 b because the protruding edges of the glass core layer are not undercompressive stress that resists flaw generation. In some embodiments,the heat applied to the desired line of separation may direct the flawacross the desired line of separation.

In some embodiments in which the flaw initiation device 156 includes ascoring device, the scoring device scores a small width of thecontinuous glass ribbon 170 at the desired line of separation, such asin embodiments in which the scoring device scores a 100 mm or smallerwidth of the continuous glass ribbon 170 at an edge of the continuousglass ribbon 170. In some embodiments, the flaw initiation device 156 isconfigured to initiate a flaw at an edge of the continuous glass ribbon170. In embodiments that mechanically score the continuous glass ribbon170 across only a portion of the desired line of separation, a scoringwheel and/or other components of the scoring device may last longer,leading to cost savings realized from less frequent replacement of suchcomponents. Furthermore, in embodiments that mechanically score thecontinuous glass ribbon 170 across only a portion of the desired line ofseparation, the scoring device may be less likely to strike apre-existing crack in the ribbon, leading to a reduced likelihood of thenegative consequences of the scoring device striking a pre-existingcrack while scoring. In embodiments that heat the continuous glassribbon 170 across the desired line of separation as described herein,edge flaws typical of mechanical scoring may be reduced.

In some embodiments, the flaw initiation device 156 includes at leastone device other than a scoring device. For example, in someembodiments, the flaw initiation device 156 includes a laser, anultrasonic transducer, a carbide tip, a diamond tip or stylus, a hotfilament, a cooling apparatus, a heater (e.g., a silicon nitrideheater), a drop or stream of fluid (e.g., water, air, etc.) or the like.In some embodiments, the flaw may be initiated by a drop of waterapplied by a damp object. In some embodiments, fluid (e.g., water, air,etc.) may be applied before, during, or after the flaw initiation device156 initiates a flaw in the continuous glass ribbon 170 at the desiredline of separation, in order to enhance the initiated flaw. In someembodiments, the flaw initiation device 156 may include a mechanicalflaw initiation device (e.g., a scoring device, a tip or stylus, or thelike) as well as an auxiliary heater, which may function to enhanceseparation as described herein.

Still referring to FIG. 1 , the flaw initiation device 156 is positionedon the translatable separation initiation unit 150 relative to theheating apparatus 154 such that the continuous glass ribbon 170 isdisposed between the heating apparatus 154 and the flaw initiationdevice 156 when the heating apparatus 154 contacts the continuous glassribbon 170. In other embodiments, the flaw initiation device 156 ispositioned on the same side of the translatable separation initiationunit 150 as the heating apparatus 154 such that the heating apparatus154 contacts a first side of the continuous glass ribbon 170 along thedesired line of separation and the flaw initiation device 156 initiatesa flaw in the first side of the continuous glass ribbon 170 at thedesired line of separation. In some embodiments, the flaw initiationdevice 156 is included in the heating apparatus 154. In some embodimentsin which the heating apparatus 154 includes the flaw initiation device156, the flaw initiation device 156 is positioned at an end of theheating apparatus 154 such that the flaw initiation device 156 isconfigured to introduce a flaw in an edge of the continuous glass ribbon170 when the heating apparatus 154 contacts the continuous glass ribbon170.

Some embodiments do not include a flaw initiation device 156, such asembodiments in which a glass sheet separates from the continuous glassribbon 170 at the desired line of separation as a direct result ofheating the continuous glass ribbon 170 at the desired line ofseparation, or as a result of heating the continuous glass ribbon 170 atthe desired line of separation and imparting a bending moment to thecontinuous glass ribbon 170 about the desired line of separation. Inembodiments that do not include the flaw initiation device 156, costsavings can be realized in equipment and service as a result of notrequiring the flaw initiation device 156 to initiate separation of aglass sheet from the continuous glass ribbon 170.

In some embodiments, the translatable separation initiation unit 150 mayalso include a counternosing, which may stabilize the continuous glassribbon 170 as the continuous glass ribbon 170 is heated by the heatingapparatus 154, maintain flush contact between the continuous glassribbon 170 and the heating apparatus 154, and/or reduce vibration up thedraw during separation. In embodiments that include the counternosing,the heating apparatus 154 may contact a first side of the continuousglass ribbon 170 at the desired line of separation and the counternosingmay contact a second side of the continuous glass ribbon 170 at thedesired line of separation when the heating apparatus contacts the firstside of the continuous glass ribbon 170 at the desired line ofseparation. In some embodiments, the counternosing may include the flawinitiation device 156. In some embodiments that include thecounternosing, the flaw initiation device 156 may be coupled to thecounternosing.

Embodiments may include one or more counternosings in a variety ofconfigurations. For example, FIG. 6 depicts a portion of a translatableseparation initiation unit that includes the heating apparatus 154 and anosing 159 configured to contact a first side of the continuous glassribbon 170 at the desired line of separation, and a counternosing 180configured to contact a second side of the continuous glass ribbon 170at the desired line of separation when the heating apparatus 154contacts the first side of the continuous glass ribbon 170. Thecounternosing 180 depicted in FIG. 6 has a width greater than or equalto a width of the continuous glass ribbon 170 such that thecounternosing 180 is in contact with the second side of the continuousglass ribbon 170 at the desired line of separation across the entirewidth of the continuous glass ribbon 170. In some embodiments, thecounternosing 180 may have a width slightly less than the width of thecontinuous glass ribbon 170, such that the width of the counternosing180 is less than the width of the continuous glass ribbon 170, butgreater than 75% of the width of the continuous glass ribbon 170.

FIG. 7 depicts a portion of a translatable separation initiation unitthat includes the heating apparatus 154 and a nosing 159 configured tocontact a first side of the continuous glass ribbon 170 at the desiredline of separation, and a counternosing 182 configured to contact asecond side of the continuous glass ribbon 170 at the desired line ofseparation when the heating apparatus 154 contacts the first side of thecontinuous glass ribbon 170. The counternosing 182 depicted in FIG. 7has a width smaller than the width of the continuous glass ribbon 170and is configured to contact a central portion of the continuous glassribbon 170 when the heating apparatus is in contact with the continuousglass ribbon 170 at the desired line of separation.

FIG. 8 depicts a portion of a translatable separation initiation unitthat includes the heating apparatus 154 and a nosing 159 configured tocontact a first side of the continuous glass ribbon 170 at the desiredline of separation, and a first counternosing 184 a and a secondcounternosing 184 b configured to contact a second side of thecontinuous glass ribbon 170 at the desired line of separation when theheating apparatus 154 contacts the first side of the continuous glassribbon 170. The first counternosing 184 a and the second counternosing184 b are spaced apart widthwise and configured to contact bead portionsof the continuous glass ribbon 170 when the heating apparatus is incontact with the continuous glass ribbon 170 at the desired line ofseparation. In some embodiments, the counternosing is restricted to theregion of the clad bead and knurl at each edge of the continuous glassribbon 170. The configuration shown in FIG. 8 can help to ensure contactbetween the heating apparatus 154 and the bead and/or knurl regions ofthe glass ribbon 170 at the desired line of separation.

The nosings and/or counternosing described herein may be formed from avariety of materials, including aluminum, stainless steel,alumino-silicate fibers, silicone rubber, plastic, or the like.Furthermore, some embodiments may utilize a backing or support fixtureinstead of a nosing or counternosing. Some embodiments may include aheating apparatus in the counternosing or may include a heatingapparatus that contacts a second side of the continuous glass ribbon 170instead of the counternosing. While the embodiments of FIGS. 6-8 includethe nosing 159 configured to contact the first side of the continuousglass ribbon 170, some embodiments do not include the nosing 159, suchas embodiments in which only the heating apparatus 154 contacts thefirst side of the continuous glass ribbon. In some embodiments thatinclude one or more counternosings, the one or more counternosings maybe configured to contact the continuous glass ribbon above or below thedesired line of separation.

Referring now to FIG. 9 , a side view of the continuous glass ribbon 170in engagement with a nosing 159, a first counternosing 186, the heatingapparatus 154, the flaw initiation device 156, and a secondcounternosing 188 is schematically depicted. The continuous glass ribbon170 may be pressed between the nosing 159 and the first counternosing186, such that the nosing 159 and the first counternosing 186 engage thecontinuous glass ribbon 170 therebetwen. The continuous glass ribbon 170may be heated along a desired line of separation by the heatingapparatus 154. The flaw initiation device 156 may initiate a flaw in thesecond side of the continuous glass ribbon 170 (either before, during,or after the continuous glass ribbon 170 is heated along the desiredline of separation by the heating apparatus 154). A sheet of glass maybe separated from the continuous glass ribbon at the desired line ofseparation by the second counternosing 188, which moves in the −Ydirection to separate the glass sheet from the continuous glass ribbon170. In some embodiments, each of the nosing 159, the firstcounternosing 186, the second counternosing 188, the heating apparatus154, and the flaw initiation device 156 may be components of thetranslatable separation initiation unit 150 described herein, though inother embodiments, one or more of the nosing 159, the firstcounternosing 186, the second counternosing 188, the heating apparatus154, and the flaw initiation device 156 may be separate from thetranslatable separation initiation unit 150. In some embodiments, one ormore of the nosing 159, the first counternosing 186, and the secondcounternosing 188 may instead be a heat sink or cooling apparatus.

In some embodiments, the glass manufacturing apparatus may include acooling apparatus configured to contact the continuous glass ribbon 170at the desired line of separation. In some embodiments, the coolingapparatus extends perpendicular to the draw direction and is configuredto contact the continuous glass ribbon 170 across at least a portion ofthe width of the continuous glass ribbon 170 at the desired line ofseparation as the continuous glass ribbon 170 moves in the drawdirection. For example, referring now to FIG. 10 , the continuous glassribbon 170 is disposed between the heating apparatus 154 and a coolingapparatus 190, such that the heating apparatus 154 contacts a first sideof the continuous glass ribbon 170 at the desired line of separation andthe cooling apparatus 190 contacts a second side of the continuous glassribbon 170 at the desired line of separation. In some embodiments, thecooling apparatus 190 extends parallel to the draw direction or extendsat an angle between 0° and 90° relative to the draw direction.

In embodiments that include the cooling apparatus 190, the coolingapparatus 190 may include a cold wire, a cold rod, a cold tube, oranother cold element having a temperature less than the continuous glassribbon 170 at the location at which the cooling apparatus 190 cools thecontinuous glass ribbon 170. In some embodiments, the cooling apparatus190 is actively cooled, such as by circulating cold water through thecooling apparatus 190. In other embodiments, the cooling apparatus 190may be at ambient temperature. In some embodiments, the coolingapparatus 190 is a component of the translatable separation initiationunit 150, though in other embodiments the cooling apparatus 190 may beseparate from the translatable separation initiation unit 150. In someembodiments, the cooling apparatus 190 may contact the continuous glassribbon 170 above or below the desired line of separation. In someembodiments, a second side of the continuous glass ribbon 170 may becooled at the desired line of separation, a first side of the continuousglass ribbon 170 may be heated at the desired line of separation by theheating apparatus 154, and the second side of the continuous glassribbon 170 may be cooled by the cooling apparatus 190 to facilitateseparation (e.g., thermal shock separation resulting from applying thecooling apparatus 190, or enhancing mechanical separation by the glassengaging unit 160, for example).

Referring now to FIG. 11 , the heating apparatus 154 and the coolingapparatus 190 are disposed on the same side of the continuous glassribbon 170, such that the heating apparatus 154 first contacts a firstside of the continuous glass ribbon 170 at the desired line ofseparation and the cooling apparatus 190 then contacts the first side ofthe continuous glass ribbon 170 at the desired line of separation. Thecooling apparatus 190 may include a cold wire, a cold rod, a cold tube,or any other cold element having a temperature less than the temperatureof the continuous glass ribbon 170 at the location at which the coolingapparatus 190 cools the continuous glass ribbon 170. In someembodiments, the cooling apparatus 190 is actively cooled, such as bycirculating cold water through the cooling apparatus 190. In otherembodiments, the cooling apparatus 190 may be at ambient temperature. Insome embodiments, the cooling apparatus 190 is a component of thetranslatable separation initiation unit 150, though in other embodimentsthe cooling apparatus 190 may be separate from the translatableseparation initiation unit 150. In some embodiment, the coolingapparatus 190 and the heating apparatus 154 may be coupled to a drum,which may be rotated such that the heating apparatus 154 first contactsthe continuous glass ribbon 170 and then the cooling apparatus 190contacts the continuous glass ribbon 170 (e.g., by rotating the drum tomove the heating apparatus away from the glass ribbon and the coolingapparatus toward the glass ribbon). In some embodiments, the coolingapparatus 190 may contact the continuous glass ribbon 170 above or belowthe desired line of separation. Some embodiments that include a coolingapparatus may not include a heating apparatus, such as embodiments inwhich a cooling apparatus engages the continuous glass ribbon 170 andthermally induces separation. Not to be bound by theory, but it isbelieved that separation of a glass sheet from the continuous glassribbon 170 at the desired line of separation is enhanced by the methodsand apparatuses described herein that include a heating apparatus and acooling apparatus because the continuous glass ribbon initially includescompression regions in the cladding layers and a tension region in thecore layer, heat applied to a cladding layer at the desired line ofseparation reduces the compression of the cladding layer, and a rapidthermal shock by cooling the cladding layer changes the cladding layerto a tension state quickly, causing the continuous glass ribbon 170 toseparate at the desired line of separation.

Some embodiments may apply the principles herein to separate beads froma central portion of the continuous glass ribbon 170 by heating thecontinuous glass ribbon along desired lines of separation that extend inthe draw direction, and subsequently separating the beads from thecentral portion along the desired lines of separation.

Referring now to FIG. 12 , additional components of an embodiment of thetranslatable separation initiation unit 150 are depicted. Thetranslatable separation initiation unit comprises a frame 70 and acarriage assembly 72 coupled thereto. Frame 70 may be rigidly coupled tostructural components of the facility in which the glass makingapparatus is housed. For example, frame 70 may be rigidly coupled to thestructural steel or concrete of a factory building. In the embodimentdepicted in FIG. 12 , travel screws 74 are rotatably mounted on frame 70and extend between an upper frame member 76 and a lower frame member 78.Travel screws 74 may be coupled to at least one motor configured to turnthe travel screws. For example, FIG. 12 depicts a single motor 80driving two travel screws 74 through gear boxes 82, a transmission 84and drive axles 86. Other arrangements are possible.

Carriage assembly 72 includes at least one follower nut coupled theretoand through which a travel screw 74 passes. As a travel screw 74 turns,the follower nut travels along the screw in a direction dependent on thedirection of rotation of the screw, therefore driving the carriageassembly in the direction of the follower nut. The heating apparatus 154is coupled to the carriage assembly 72. For example, the heatingapparatus 154 may be coupled to the carriage assembly 72 by one or morelinear slides 88 configured to extend or retract the heating apparatus154 toward or away from the continuous glass ribbon 170, respectively,in a direction orthogonal to the draw direction. In the extendedposition, the heating apparatus 154 is engaged with (e.g. contacting)the continuous glass ribbon 170. In the retracted position, the heatingapparatus 154 is disengaged from the continuous glass ribbon 170.

The carriage assembly 72 may further comprise the flaw initiation device156, which is coupled to the carriage assembly 72 through the rail 90.The flaw initiation device 156 is driven along the rail 90 by any drivemechanism capable of traversing the flaw initiation device 156 in asuitably precise path. For example, the flaw initiation device 156 maybe driven along the rail 90 by a travel screw and follower nut in amanner similar to the arrangement for the carriage assembly 72. Inembodiments in which the flaw initiation device 156 is a scoring device,pneumatic operation of the scoring device may be used. Such a scoringdevice may also include one or more pneumatic or stepper motor-activatedlinear slides configured to extend or retract the scoring device, or aportion thereof, toward the continuous glass ribbon 170 or away from thecontinuous glass ribbon 170, respectively, in a direction orthogonal tothe draw direction. In the extended position, the scoring device isengaged with (e.g. contacting) the continuous glass ribbon 170. In theretracted position, the scoring device is disengaged from the continuousglass ribbon 170. In some embodiments, scoring may be accomplished in anon-contact manner, wherein scoring is accomplished by way of a laserbeam. In such cases, extension and retraction of the scoring device maynot be necessary. In some embodiments, the scoring device produce ascore that is substantially perpendicular to the draw direction.

It should be understood that the translatable separation initiation unit150 is not limited to the embodiments described herein. In someembodiments, the translatable separation initiation unit 150 may includea carriage assembly that is moved along a frame in a manner other thanwith travel screws and follower nuts. For example, in some embodiments,a carriage assembly may be moved with one or more linear actuatorsoperable to translate the carriage assembly in the draw direction andopposite the draw direction.

A method of heating a moving continuous glass ribbon and for separatinga glass sheet from the moving continuous glass ribbon will now bedescribed

Referring once again to FIG. 1 , molten glass is drawn from the formingbody 110 by the plurality of pulling rolls 140 to form the continuousglass ribbon 170. The continuous glass ribbon 170 moves from the formingbody 110 with a velocity vector Vr comprising a speed S in the drawdirection. The translatable separation initiation unit 150, whichincludes the heating apparatus 154 moves in the draw direction from aninitial start position and attains a velocity that matches that of themoving continuous glass ribbon 170. That is, the translatable separationinitiation unit 150 acquires a velocity vector Vt that matches thevelocity vector of the glass ribbon. Accordingly, the heating apparatus154 (and the translatable separation initiation unit 150 of which theheating apparatus 154 is a component) and the continuous glass ribbon170 simultaneously travel at the speed S in the draw direction.

As the continuous glass ribbon 170 moves, the translatable separationinitiation unit 150 contacts and heats the continuous glass ribbon 170with the heating apparatus 154 across at least a portion of a width ofthe continuous glass ribbon 170 at a desired line of separation (“DLS”)(e.g., by extending the heating apparatus 154 to be in contact with thedesired line of separation, as described above with reference to FIG. 12). Referring to FIG. 2 , the desired line of separation extendslaterally across the draw in a direction perpendicular to the drawdirection. As noted above, embodiments are not limited to the desiredline of separation extending laterally across the draw in a directionperpendicular to the draw direction. For example, in some embodiments,the translatable separation initiation unit 150 contacts and heats thecontinuous glass ribbon 170 with the heating apparatus 154 at a desiredline of separation that extends parallel to the draw direction or at anangle of between 0° and 90° relative to the draw direction.

Referring once again to FIG. 1 , a sheet of glass may then be separatedfrom the continuous glass ribbon 170 at the desired line of separation.In some embodiments, separating the sheet of glass from the continuousglass ribbon 170 may include initiating a flaw at the desired line ofseparation with the flaw initiation device 156 described above. In someembodiments, the flaw initiation device 156 may be a scoring device thatscores the continuous glass ribbon 170 at the desired line ofseparation. It should be apparent that to produce a score that isperpendicular to the edge portions of the moving continuous glass ribbon170 the scoring device must also move such that there is no relativemotion between the scoring device and the glass ribbon in the drawdirection during the scoring process. After carriage assembly 72 (SeeFIG. 12 ) has attained a speed equal to or substantially equal to thespeed of the glass ribbon in the draw direction, the heating apparatus154 is extended to contact the continuous glass ribbon 170. Thetranslatable separation initiation unit 150 may initiate a flaw at thedesired line of separation with the flaw initiation device 156 eitherbefore heating, while heating, or after heating the continuous glassribbon 170 at the desired line of separation.

Still referring to FIG. 1 , in some embodiments, separating the glasssheet from the continuous glass ribbon 170 may involve the glassengaging unit 160. The glass engaging unit 160 includes a body 162, anarm 164, a platform 166, and a plurality of gripping devices, such assuction devices 168. The arm 164 extends from the body 162. The platform166 is positioned at a distal end of the arm 164. Suction devices 168(e.g. suction cups and/or vacuum chucks) are arranged on the platform166 and are configured to engage with edge portions of the “A” side ofthe glass ribbon. The arm 164 moves the platform 166 at a velocityvector Vra that matches the velocity vector Vr of the continuous glassribbon 170 such that the continuous glass ribbon 170, the translatableseparation initiation unit 150 (including the heating apparatus 154 andthe flaw initiation device 156) and the platform 166 are all moving intandem and there is no relative motion between them in the drawdirection. In other words, the glass engaging unit 160 through the arm164 causes the platform 166 to track with the continuous glass ribbon170. When the platform 166 is tracking with the continuous glass ribbon170 so that no relative motion in the draw direction between theplatform and the glass ribbon is occurring, the arm 164 moves theplatform 166 such that suction devices 168 engage with the glass ribbonbelow the desired line of separation. In some embodiments, the suctiondevices 168 may be spaced apart from the heating apparatus 154 by about100 mm to about 200 mm, such as about 150 mm. Once the continuous glassribbon 170 has been heated at the desired line of separation (and anyflaws have been initiated in embodiments that initiate a flaw with theflaw initiation device 156 and/or the desired line of separation hasbeen cooled with the cooling apparatus in embodiments that do so), thearm 164, now coupled to the continuous glass ribbon 170, imparts abending moment to the continuous glass ribbon 170 about the desired lineof separation to separate a glass sheet from the continuous glass ribbon170. The arm 164 remains coupled to the separated glass sheet and movesit to a receiving station. The glass engaging unit 160 can, for example,deposit the glass sheet onto a conveyor assembly that moves the glasssheet for downstream processing (such as removal of the edge portions ofthe glass sheet, edge finishing, washing, etc.). Once the glass sheethas been deposited at the next process, the arm 164 is returned to astart position, prepared to separate and convey another glass sheet. Inembodiments that heat the continuous glass ribbon 170 at the desiredline of separation as described herein, the angle at which the glassengaging unit 160 must bend the continuous glass ribbon 170 to separatethe glass sheet from the continuous glass ribbon 170 may be reduced,thereby mitigating post-separation motion imparted to the remainder ofthe continuous glass ribbon 170. In some embodiments, the methodcomprises bending the continuous glass ribbon at the desired line ofseparation to a bend angle less than or equal to about 20°, less than orequal to about 15°, in the range from about 10° to about 20°, or in theranged from about 10° to about 15°. Such bend angle ranges may besmaller than the approximately 25° bend angle that may be required toseparate a glass sheet from a continuous glass ribbon not heated alongthe desired line of separation as described herein. Such a smaller bendangle may desirably result in better stability of the continuous glassribbon 170 and decreased movement of the ribbon in the +Y and −Ydirections upon separation of a glass sheet from the continuous glassribbon 170. In some embodiments, the glass engaging unit 160 may beconfigured as a robot, though embodiments are not limited thereto. Insome embodiments, it may be desirable to separate the glass sheet fromthe continuous glass ribbon 170 within about 3-8 seconds from initiallycontacting the continuous glass ribbon 170 with the heating apparatus154.

It should now be understood that the apparatuses and methods for heatingmoving continuous glass ribbons at desired lines of separation and/orfor separating glass sheets from continuous glass ribbons produce glasssheets with enhanced edge quality, reduced vertical cracking, andreduced warping, as compared to glass sheets separated from continuousglass ribbons by conventional separation techniques.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the embodiments describedherein without departing from the spirit and scope of the claimedsubject matter. Thus it is intended that the specification cover themodifications and variations of the various embodiments described hereinprovided such modification and variations come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A method of separating a glass sheet from acontinuous glass ribbon, the method comprising: drawing molten glass ina draw direction at a speed S from a forming body to form the continuousglass ribbon, the continuous glass ribbon comprising a core layerdisposed between a first cladding layer and a second cladding layer;directing the continuous glass ribbon by a translatable separationinitiation unit positioned downstream of the forming body, thetranslatable separation unit comprising: a support portion, and aheating apparatus coupled to the support portion and configured tocontact the continuous glass ribbon across at least a portion of a widthof the continuous glass ribbon at a desired line of separation as thesupport portion moves in the draw direction, the heating apparatuscomprising a heating element and an insulating tube, wherein the heatingelement is disposed at least partially within the insulating tube andprotrudes through an elongate aperture in the insulating tube, andwherein the insulating tube is coupled to the support portion by anelement that traverses a body of the insulating tube; moving the heatingapparatus in the draw direction at the speed S; applying heat to a firstside of the continuous glass ribbon at the desired line of separationwith the heating apparatus as the continuous glass ribbon moves in thedraw direction; initiating a flaw in the continuous glass ribbon at thedesired line of separation; and separating the glass sheet from thecontinuous glass ribbon at the desired line of separation.
 2. The methodof claim 1, wherein the applying heat to the first side of thecontinuous glass ribbon comprises contacting the continuous glass ribbonwith the heating apparatus at the desired line of separation as thecontinuous glass ribbon moves in the draw direction at the speed S. 3.The method of claim 1, wherein: an exposed portion of the core layerextends beyond the first cladding layer and the second cladding layer atan edge region of the continuous glass ribbon; and scoring the corelayer of the continuous glass ribbon without scoring either of the firstcladding layer or the second cladding layer comprises scoring theexposed portion of the core layer.
 4. The method of claim 1, wherein thecore layer comprises an average coefficient of thermal expansionCTE_(core) that is greater than an average coefficient of thermalexpansion CTE_(clad) of each of the first cladding layer and the secondcladding layer.
 5. The method of claim 1 wherein separating the glasssheet from the continuous glass ribbon at the desired line of separationcomprises imparting a bending moment to the continuous glass ribbonabout the desired line of separation.
 6. The method of claim 1 furthercomprising cooling the continuous glass ribbon at the desired line ofseparation with a cooling apparatus.
 7. The method of claim 1 whereininitiating the flaw in the continuous glass ribbon at the desired lineof separation comprises scoring the core layer of the continuous glassribbon without scoring either of the first cladding layer or the secondcladding layer.